Blast tube for machine guns



W. R. FLETCHER BLAST TUBE FOR MACHINE GUNS Filed April 18. 1922 Wwf/*Tw www Patentedl oct. 2o, 1925.

- UNITED STATES WALLACE R. FLETCHER, OF DAYTON, OHIO.

BLAST TUBE FOR MACHINE GUNS.

Application led April 18, 1922. Serial No. 555,269.

To all whom-1fv may concern.'

Be it known that I, WALLACE R. F Lm'ox-IER,

a citizen o f the United States, residing'at Dayton, in the county of Montgomery and State of Ohio, have invented certain new and useful Improvements in Blast Tubes for Machine Guns (Case A), of which the following is aspecification.

My invention relates to a blast tube for machine guns. The purpose of such a tube is to convey the blast or flash from the muzzle of the gun forward through any section or past any material or equipment which it is necessary to protect against fire or blast effect.

It is particularly important to protect u parts of airplanes from exposure to tire and blast effect of the machine gunsmounted thereon.. In a fixed gun mount t-he machinegun is usually placed so far to the rear that the muzzle does not project through the f cowl of the airplane and it becomes onev of the functions of the blasttube to carry the ment and gases of the machine the cowl.

The main objects of my invention are.to provide a blast tube of simple and sturdy construct-ion which can be easily 'applied in firm relation to t-he machine gun.

By using a tube of my improved const-ruction in a gun which fires between the propeller blades, the hot gases and flame are carried forwardly past the propeller blade, before the blade has revolved far enough to be inthe line of fire.

For illustrative purposes the specification describes, and the accompanying drawings show the invention applied to the type of gun known as the Vickers aircraft machine um g In the drawings:

Figure 1 is a side elevation of the blast tube and part of a machine gun to which it is applied;

Figure 2 is a sectional view on the line 2--2 of Fig. 1 and Figure 3 is a detail sectional view showing the relation between the muzzle attachblast tube.

The numeral 10 designates a barrel jacket gun forward through which is preferably a corrugated cylinder,

formed from drawn-steel tubing and ventilated near both its forward and rear ends to permit free circulation of air around the barrel 11, the forwardy vents being indicated at 12. The barrel jacket cap 13, is a steel forging and closes the forward end of the barrel jacket, except for Ventilating holes formed therein. A stulling box 14 and follower 15 are screwed in the rear and front' respectively of a cylindrical opening 16 formed through the face of the jacket cap 13 at the lower portion thereof. The stuffing box flares outwardly toward the rear Vin orderl to act as a guide in assembling the barrel. The follower is provided with an in-` ner annular flange 17 of reduced diameter which screws into the opening 16 and with an outer annular flange 18 having several holes 19 therein. A cylindrical sleeve 20 is connected to the flange 18 by annular interrupted rings 21 and is formed with a hole adapted to register with one of t-he holes 19 for receiving a split locking pin 22. For convenience the pin 22 is carried at one end of a. chain 23, the other end of which is provided with an S-hook engaging an eye bolt 24 secured to the barrel jacket cap 13. The sleeve 20 projects forwardly of the flange 18 and is formed withl an annular row of apertures 25 throughwhich the explosion gases ma have a restricted flow. The forward en. of the sleeve 20 is closed, except for the axial by the front disk 26 which is screwed' in place. The forward end of the gun barrel 11 has detachably secured thereto a disk 27. The device comprising the follower, sleeve and front disk is termed a muzzle attachment and its function is to increase the recoil action of the barrel. The 'bullet when fired causes a recoil of the gun barrel and the attached disc 27 relatively to the rest of the passage allowing escape of the bullet,

gun. This recoil action is assisted by the communicate with the chamber when the barrel has recoiled. The openings 25 conduct the gases to the rear part of the blast tube. It will be understood that the particular form of muzzle attachment has been described' for illustrative purposes only and that my invention may be applied to muzzle attachments of different form and construction.

According to my invention a tube 30 is of such diameter at one end 31 as to t snugly over the sleeve 20. This portion of the tube is provided with an opening adapted to register with a like hole in the sleeve and one of the holes 19 for the purpose of receiving p1n 22 which thus locks the blast tube in position. The tube is formed with an enlarged section 32 which extends around the sleeve 20 at the apertures 25 in order to provide a. chamber 33 for receiving the explosion gases issuing through said apertures. 4This enlarged section is preferably welded to the forward body portion of the tube 30 and the end piece 31 at the tapered and abrupt shoulders 34, 35 respectively. The body portion of the tube in front of the shoulder 34 extends forwardly suicient to protect the parts of the airplane or its equipment from exposure to fire and blast eiect. The end piece 31 by tightly engaging the sleeve of the muzzle attachment insures against any leakage of dame or blast except through the forward open end of the blast tube.

The explosion gases issuing through the restricted apertures 25 are received in chamber 33 and are conveyed from thence through theltube to the open end thereof. The removable pin 22 prevents forward and backward movement of the blast tube with relation to the muzzle attachment.

I claim:

1. A device adapted to be attached to the forward end of a machine gun to carry the flash rapidi forwardly, consisting of a cylindrical tu ular part open at its front end and extending from a point near the end of the gun barrel to a point considerably fora point considerably forward of the same,

A. blast tube adapted to be attached to said part being considerably larger than the bore of the gun and an enlarged rear part adapted to be connected to the forward end ofthe gun and supporting said cylindrical tubular part, said enlarged rear part adapted to communicate with a recoil muzzle attachment to carry the gases from the same tothe forwardcylindrical tubular part, the opening at the front end of the. forward cylindrical part providing the only exit for the gases from the blast tube.

3. The combination with a muzzle attachment for a machine gun having a series of apertures formed therein, a blast tube having a portion thereof mounted on said muzzle attachment and being provided with an aperture for ali nment with one of said apertures in sai muzzle attachment, and

means passing through said aligned aper` tures to retain said tube and said muzzle attachment in operative position.

In testimony whereof I aiix my signature.

WALLACE R. FLETCHER. 

